Gal. 5:16-25 New International Version (NIV)
16 So I say, walk by the Spirit, and you will not gratify the desires of the flesh.17 For the flesh desires what is contrary to the Spirit, and the Spirit what is contrary to the flesh. They are in conflict with each other, so that you are not to do whatever you want. 18 But if you are led by the Spirit, you are not under the law.
19 The acts of the flesh are obvious: sexual immorality, impurity and debauchery; 20 idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions 21 and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God.
22 But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness, 23 gentleness and self-control. Against such things there is no law. 24 Those who belong to Christ Jesus have crucified the flesh with its passions and desires. 25 Since we live by the Spirit, let us keep in step with the Spirit.
From the time of regeneration of a person, there begins a war within himself – the flesh and the Spirit warring against each other. The flesh would want to dominate and thereby make the believer sin and do acts that would displease God. The Spirit on the other hand would want the believer to walk obediently in the ways of God. The apostle Paul says, “Walk in the Spirit, and you shall not fulfill the lust of the flesh” (Gal. 5:16).
Are you contentious, having feelings of jealousy, lust, hatred, adultery, and are you concerned only with the things of this world? Paul says these are works of the flesh and that those who practise such things will not inherit the kingdom of God (Gal. 5:19-21). Is there a truth in the Bible that instantly awakens irritability in you? That would be a sign that there is some element of carnality in you. If the Spirit of God detects anything in you that is wrong, God is telling you to put it right. A child of the light confesses instantly and stands exposed before God; a child of the darkness would try to make excuses and explain the sin away. When the light of God’s truth breaks in and the conviction of wrong comes, confess your sin and God will deal with what is wrong. If you justify yourself, you prove yourself to be a child of the darkness.
God expects you to daily walk in His Spirit, the way the Holy Spirit charts out for you. God will not forcefully cause you to walk in His Spirit. You have to walk in His Spirit. The volition to walk is yours. The flesh will always want to assert itself and trip you down in sin. But if you would listen to the voice of the Spirit when He tugs at your heart, if you commit yourself to obey His leading, then He will surely help you not to fulfill the lust of the flesh.